Trimming mechanism for sewing machines



A. H. DE VOE. TRIMMING MECHANISM FOR SEWING MACHINES. APPLICATION FILED JUNE 22,1918 1 43159359 Patented Oct. 17, 1922.

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I! INVENTOR WITNEZiE I m/KflZ/ 9 0 ATTORNEY A. H. DE VOE. TRIMMING MECHANISM FOR SEWING MACHINES.

APPLICATION FILED JUNE 22. IBIS.

Patented Oct. 17,1922.

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.. fll I Ind TOR WITNESSES INVEN fl k);

ATTORNEY rel ALBERT H. DE VOE, OF WES'I'FIELD, NEW- JERSEY,

.z'LFSSIGNUR TO THE SINGER MANU- FACTUBING CUMEANY, A. CORFEQIRATION 035 NEW' JERSEY.

TRIMMING MECHANISM SEVTIllGr MACHINES.

Original application filed January 27, 1917, Serial No. 144,847. Divided Serial No. 241,368.

To all whom it may concern:

Be it known that I, ALBERT H. DE Von, a citizen of the United States, residing at Westfielchin the county of Union and State of New Jersey, have invented certain new and useful Improvements in Trimming Mechanisms for Sewing Machines, of which the following is a specification, reference being had therein to the accompanying drawings.

This invention relates to a trimming mechanism, such as that shown in my copending application Serial No. 1445,84 7, filed January 27, 1917, of which this application is a division.

It has been common to support theblades of the trimming mechanism on a rigid resser-foot. When such a presser-foot meets a seam or other irregularity in the material being sewed it is abruptly raised and held so until the irregularity is passed when it is abruptly lowered. As the trimmerblades are raised and lowered simultaneously with the presser-foot, abrupt projections are formed in the cut edge portions of the material of a length equal to that of the presser-foot. In order that the seam may be closed at each side of these projections the material constituting them must be crowded or bunched together, resulting in unsightly and uneven work.

The object of the present invention is to provide a trimming mechanism which will trim the meeting edge portions of material with the greatest possible uniformity under varying conditions, such irregularity in the thickness of the material, cross-seams, 85c, whereby a strong flat seam may be produced.

In the present embodiment the presserfoot has a shank provided with a fiat extension and a pivoted sole portion arranged side by side. The sole portion is slotted to provide spaced toes between which the upturned edge portions of material are guided to a trimmer, the latter consisting of a ledger-blade secured to the flat extension and spaced slightly from the sole portion, and a cutting blade mounted on a vibratory arm at the lower end of a rock-shaft journaled in the machine head. This rock-shaft is spring-pressed downwardly and is oscillated by a link connection to an arm on the needle-actuating lever.

in S115 ti carrying the throat-plate 7.

and this application filed June 22,

dteferring to the drawings, Fig. l is a 5 side elevation partly in section and with the supporting means partly broken away, showlng'a feed-olt-the-arm sewing machine with my trimming mechanism applied thereto. Fig. 2 is a rear elevation of the machine 6 frame partly in section and with parts broken away. Fig. 3 is a plan of the presserfoot and trimming blades showing the presser-bar in section. Fig. t is a perspective of the presser-it'oot and trimmer. Fig. 6 5 is a section through the trimmer on the line 5-5 of Fig. 1, but showing the trimmerblades closedf [is shown in the drawings, the machine frame includes a depending support 1 secured at its upper end in any desired way, and enlarged laterally at its lower end to forms body portion 2 in which is mounted Jble bearings a main-shaft 3 carrying a pulley driven by a belt (not shown) connected to a drive pulley located at the upper end oi thesupport 1. Extending downwardly and rearwardly from the body 2 is a hollow L-shaped work-arm 4 comprising a vertical portion and a horizontal portion Mounted in the arm and driven from shaft 3 are a looper mechanism and feed-dogs which form no part of the present invention. Disposed above th work-arm is a head 8 carried by a bracket-arm 9 connected to the body 2, the arm 9 being arranged at one side of the center line ot the work-arm, whereby the operator may have an unobstructed. view of the work. The shalt 3 carries a sphericalshaped crank 10 connected by a link 11 at 12 to one end of a needlc-actuating arm 13 fulcruined at 14- on the bracketnrm. The other end oi the needlc-arm 13 has a pivotal connection at 15 with a link 16 pivotally connected to a split sleeve 17 on a needle-bar 18, the latter carrying at its lower end pairs .of needles 19 and 20 Mounted to slide in the bearing sleeve 21 is a presser-bar 22, which carries at its upper end a horizontal socket member 23, and within. said socketmember is iixed a pin 24 which supports at one end a vertical guidesleeve 25 slidable on a trimmer-actuating rock-shaft 26 to be presently described. I is its opposite end pin 24 is reduced and carries t v0 roller-disks 27, 28, the first of which supports one end of a eat-spring 29 the other end of which is apertured and fits over a pin 30. The pressure of the spring 29 may be regulated by a screw 31 carried by the bracket-arm 9. The disk 28 bears against a cam 32 on the manually operated presser-foot lifting lever 33 pivoted within the head 8, said lever projecting through a slotted opening. in the head. A guide-block 34 is mounted on the wardly from its pivot. The central portion of the sole-piece is apertured'at l l to receive the needles 19. Apertures are provided for the rear needles 2(). Carried by the shank 39 is a flattened extension +6, which is transversely recessed to receive the ledgerblade 47 of the trimming mechanism, said blade being secured therein by screws 48. The block 34:, lug 37 and shank 39 with its extension 46 form the body portion of the resser-foot. The toe portions of the sole piece 41 project slightly beyond the extension 46. The left-hand toe portion 43 is reduced in thickness at 43' to allow the ledgerblade to be set close to the surface of work passing under the presser-foot. The ledgerblade is spaced above the sole-piece, when operating on work of uniform thickness. The cutter-blade 41-9 is secured by screws 50 to the forwardly extended free end of a bowed arm 51 whose opposite sleeved end is secured to the lower end of the trimmeractuating rock-shaft 26 above referred to. The rock-shaft is journaled in sleeves 36 and 53 in the head 8 and has secured thereto a split collar 54 from which projects a ballended pin 55. the latter being embraced by one strapped end of a. link 56 whose opposite strapped end Fig. 1) embraces a ball-ended pin 57 carried by a short arm 58 projecting upwardly from the needle-arm 13. A coil spring 59 is interposed on shaft 26 between the bearing sleeve 53 and the split collar 54, said spring serving to yieldingly maintain the cutter-blade in contact with the ledgerblade, while allowing the latter to move vertically for varying thicknesses of material. Both trimmer-blades can also move upwardly with the presser-foot when the latter is lifted for any reason.

It will also be noted from an inspection of Fig. 5 that the lower face of the extension 46 is higher than the lower face of the pivoted sole-portion L3 so that in normal operation when the lower face of the sole-portion 43 is in contact with the surface of the work it maintains the extension 46' spaced above the work. Preferably the entire weight of the presser-foot is carried by the sole-portion.

The improved trimming mechanism operates as follows 7 As an irregularity in the material, for instance a cross-seam, reaches the toes 43 of the sole-piece and passes thereunder the toes are raised a given distance, but the trimmer-blades will at first he lifted but a fraction of this distance and will trim the upturned portions of material at a gradually increasing distance from the throatplate as the cross-seam approaches the pivot 4.0 due to the fact that as the irregularity passes under the front end of the sole-portion, this sole portion turns on the pivot -10 and this pivot with thefliixed extension 4L6 and the trimming mechanism is at first raised only a slight amount instead of the full height of the irregularity as would he the case if the sole-portion were rigid with the extension 46 or if this extension rested-on the surface of the work. After the cross-seam passes the pivot the heel portion 4-3- of the sole piece is raised and the toeportion tilts toward the throat-plate once more, and the trimming action takes place at a gradually decreasingdistance from the throat-plate until the cross-seam passes en- .tirelyfrom under the pressenfoot. As a result, the projecting portions in the adjacent cut edges caused by the cross-seam are at their maximum only immediately adjacent said seam and taper away gradually to each side fora distance approximately half the length of the presser-foot and a comparatively smooth seamcan be formed without any sudden bunching and crowding together of the material. vWith the previously used rigid presser-foot and trimmer carried thereby, the entire presser-foot is immediately raised to a maximum distance by a cross-seam, carried at this height until the seam leaves the presser-foot and then as suddenly lowered, with the result that there are abrupt projections formed in the cut edges of the material extending for approximately the entire length of the presser-foot which projections cause the. joined seam to be crowded and uneven.

It is to be understood that the invention is not limited in its application to the particular type of sewing machine illustrated. and may be modified in many ways within the scope of the appended claims.

Having thus set forth the nature of the invention, what I claim herein is 1. In a sewing machine, in combination,

means supported by said resser-foot at a point between the front end of said solepiece and the needles.

2. I11 a sewing machine, in combination, stitch-forming mechanism including a reciprocating needle, a resser-foot including a shank and a slotted sole-portion hinged thereto intermediate its "ends, and trimming mechanism including cutting means supported by said shank above said slot and adapted to act upon. the work guided by said slot in advance of said needles, said sole-portion being set at a lower level than said shank.

3. In a sewing machine, in combination, stitch-forming mechanism including a reciprocating needle, a presser-foot including a relatively fixed portion and a sole-portion hinged thereto and projecting in advance thereof, and trimming mechanism including trimmer blades supported by said relatively fixed portion and adapted to act upon the work in advance of said needles.

4. In a sewing machine, stitch-forming mechanism, a presser-foot having a fixed portion and a sole-piece movable relatively thereto and slotted to guide upturned mar ginal portions of material, a trimmer-blade carried by the fixed portion and disposed above the slot in the sole-piece, and a coacting trimmer-blade mounted independently of the presser-foot and movable relatively to the first blade and also therewith, the sole-piece having its lower surface set at a lower level than the lowest part of said fixed portion.

5. A trimmer for sewing machines comprising a resser-foot having a fixed portion and a sole-piece with a needle-aperture, trimming mechanism disposed above said solepiece and comprising cutter-blades disposed in front of said needle-aperture and adjacent thereto, said sole-piece and trimming mechanism being spaced apart vertically and relatively movable vertically, and said sole-piece having its lower surface set at a lower level than the lowest part of said fixed portion.

(3. A. trimmer for sewing machines co1nprising a presser-foot having a hinged solepiece, a needle-aperture in said sole-piece, and a trimming mechanism disposed between said aperture and the toe of said solepiece and spaced from the sole-piece.

7. A trimmer for sewing machines comprising a presser-foot having ashank and a pivotally mounted sole-piece, a portion of said sole-piece being recessed, a cutter-blade fixed to said shank and spaced above said recess when operating on work of uniform thickness, and a. movable cutter-blade coacting with the first-mentioned blade, said sole-piece having its lower surface set at a lower level than the lowest part of said shank.

8. In a sewing machine, a presser-foot having a pivotally mounted sole-piece and a relatively fixed extension, said sole-piece being recessed adjacent said extension, :1 ledger-blade carried by said extension and spaced above said recess, an independently and yieldingly mounted cutter-bladein engagement with said ledger-blade, and means for actuating said cutter-blade, said solepiece having its lower surface set at a lower level than the lowest part of said fixed extension. I

.9. A presser-foot including a slotted solepiece havingthe portions on the opposite sides of said slot rigidly connected together and adapted to exert the pressure of the presserfoot-upon the work, a needle-aperture in rear of such slot, a cutter mechanism disposed in front of said aperture and in operative relation to said slot to trim the work projecting therethrough, said cutter mechanism and the slotted portion of the sole-piece being spaced apart and relatively movable vertically as the machine sews work of irregular thickness.

10. In a trimmer for sewing machines, a presser-foot comprising a sole-piece adapted to sustain the ])IGSSQ1fOOl1 and an extension, said sole-piece being slotted to form toe portions and having a needle-aperture in rear of said slot, one of said toe portions having a recess, a cutter-blade carried by said extension and extending over said recess, and a second cutter-blade mounted independently of the presser-foot and coaoting with said first blade, said blades and the slotted portion of the sole-piece bein spaced apart and relatively movable vertically as the machine sews work of irregular thickness.

11. In a sewing machine, stitch-forming mechanism, a throat-plate having a flat work-supporting surface, a presser-foot opposed throughout its length to said fiat work-supporting surface, work-trimming mechanism cooperating therewith, and means including a. pivoted sole-piece for the presser-foot extending forwardly of the trimming mechanism and connected to grach ually lift and lower the trimming mechanism relative to the tln-oat-plate as a cross-seam passes under the presser-foot.

12. In a sewing machine, a presser-foot including a pivotally mounted sole-portion, trimming means, the forward end of said sole-portion extending under the trimming means and being movable about its pivot toward and from the trimming means and slotted to guide the work thereto.

13. In a sewing machine, a presser-foot including a relatively fixed extension and a movably mounted sole-piece provided with a needle aperture, trimming mechanism mounted on the fixed extension, and said sole-piece provided with means in front of the needle aperture for guiding the work to the trimming mechanism.

14. In a sewing machine, a presser-foot comprising a body-portion and a sole-piece pivoted at a fixed level relative to the said body-portion and adapted tomaintain the body-portion substantially out of contact relation with the Work, and a trimming mechalevelrelatiye to the bodyflaortion and adapted to maintain said body-portion substantially out of contact With the surface of the Work, and a trimming mechanism sustained 15 in substantially fixed relation to the bodyportion and arranged to operate crosswise of the seam.

In testimony whereof, I have signed my name to this specification.

ALBERT H. DE VOE. 

